hollins



Nov. 25, 1930. J. HOLLINS ELECTRODEPOSITION OF METALS Filed Jan. 22,1929 I5 Sheets-Sheet l Ill V .l llll M a v /N\/NTUR B 77 M, w

Nov. 25, 1930.- J. HOLLINS ELECTRODEPOSITION OF METALS 3 Sheets-Sheet 2Filed Jan. 22, 1929 r l I .5 a .41 3, v7/ L H022.2%;izizzzizzz Nov. 25,1930. J. HOLLINS ELECTRODEPOSITION OF METALS Filed Jan. 22, 1929 3Sheets-Sheet 3 Patented Nov. 25, 1930 UNITED; STATES PATENT OFFICE JACKHOLLINS, OF ROSEMOUNT, MIDDLEWICH, ENGLAND, ASSIG-NOR TO IMPERIALCHEMICAL INDUSTRIES LIMITED, OF LONDON, ENGLAND, A BRITISH COMPANYELECTRODEPOSITION OF METALS Application fi led January, 1929, Serial No.334,256, and in Great Britain February 25, 1928.

This invention relates to the electro-deposition of metals such asnickel, iron and copper, and has for its object to provide and comprisesimproved arrangements for ensuring an increased rate of deposition ofmetal in an economical and satisfactory manner.

Referring to the three accompanying sheets of explanatory drawingsFigure 1 is a sectlonal elevation and Figure 2 a plan view of One formof electrolyzer in accordance with my invention.

Figure 3 is a sectional elevation illustrating a modified arrangement ofelectrolyzer in accordance with the invention.

Figure 4 is a sectional plan View on the line A B of Figure 3.

Figure 5 is a general view illustrating the.

electrolyte circulating system.

The same reference letters in the different Views indicate the same orsimilar parts.

In Figures 1 and 2, 0 indicates the electrolyzer vat, b the anodecompartment, 0 the cathode compartment, d the diaphragm between the saidcompartments 6 and c, e the mandrels on to which metal deposits areto bemade and f the electrolyte inlet. The electrolyte difiuses into thecathode compartment, overflows over the notched upper edge of thediaphragm d, flows down the anode compartment and leaves the vat throughone or more outlet branches as g.

In accordance with my invention, I employ a number of mandrels e withinthe electrolyzing vat, and mount the same in common heads k, i at theiropposite ends. The said heads are inter-connected by the hollow stem jwhich has electrolyte diffusion apertures 70 therein. The upper head ihas a gear ring m secured thereto which is engaged by a pinlon n upon aVertical shaft 0 driven by worm and worm wheel from a cross shaft 12which is the prime motion shaft of the electrolyzer. By the arrangementdescribed, the mandrels are revolved about the axis of the electrolyzer.Each mandrel is gripped at its upper end by an expanding collet 9 withinthe conical interior of the sleeve 1' which is supported by the conicalbush 8 within the head *5. The use of the expandmg collets for grippingthe mandrels enables mandrels which differ in diameter to be secured inthe one set of bushes s. The bottom end of each mandrel is passed into aring or collar tin the rotating head it.

Each bush s has thereon a gear wheel-u which meshes with a commoncentral gear wheel '0 rotated from the cross shaft p by the bevelwheelsw, m. It will be seen, therefore, that not only do the mandrelsrevolve about the axis of the electrolyzer but they also rotate on theirownaxes. I am thereby enabled to neutralize the effects of unequalcurrent distribution in the electrolyzer, due, for example, to anodeirregularity and variations in diaphragm porosity, and so to obtainuniformity in the thickness of the deposits upon the mandrels.

The conical shape of the bushes s facilitates the threading of themandrels into the collars t in the lower head it. The arrangementdescribed also permits of the withdrawal of the mandrels withoutdisturbing the heads h and 71.

Each bush 8 is engaged on its upper face by spring loaded brushes 3carried in holders z pivoted to a common ring 2 to which current issupplied by brushes 3 carried in a fixed frame 4.

In the arrangement shown in Figure 3, supplementary heads 5, 6 arecarried in the upper head i and the lower head it respectively. Theheads 71., z are rotated about the axis of the electrolyzer by a pinionn as in the previous construction, and the heads 5 are rotated abouttheir axes by the gear wheel a driven from the cross shaft p by thebevel Wheels w and m. Each supplementary head'5, 6 carries the ends of aplurality of mandrels e. In Figures 3 and 4, there are four mandrelsbetween each pair of upper and lower heads. Each mandrel has a gearwheel 7 secured thereto at its upper end and the several wheels 7 on theone head 5 mesh with a common gear wheel 8 co-axial with the head. Thewheels 8 are on vertical shafts carrying gear wheels 9 which mesh with agear wheel 10 .driven by the bevel wheel as. It will be seen that withthis construction, the heads h, i turn about the electrolyzer axis, thesupplementary heads 5, 6 which are carried by the heads k, i turn abouttheir own axes, and the mandrels upon such supplementary heads also turnabout their own axes. I thereby ensure a maximum of uniformity in thedeposited metal with a high rate of deposition, in a plant which is verycompact and eflicient.

The electrical connection to the cathodes or mandrels is made by way ofbrushes 3 and y.

I have found that I can materially increase the weight of metaldeposited on the cathodes or mandrels without exceeding the currentdensity which is found to be the best for the production of satisfactorydeposits by screening the direct path between the cathodes and anode bymeans of a non-conducting screen. Thus, in Figures 3 and 4, screens 11are provided which depend from the head 2'. Such screens prevent thecurrent passing directly between the anode material and cathodes as thelatter each approach most closely to the anode material. Such screendiverts the current so that it passes to each cathode from two sides orin two paths which enables me to increase the current magnitude withoutincreasing the current density in either path. I thus obtain depositionat a higher rate without materially increasing the cost of the plant.

The electrolyte is supplied to the electrolyzer from a filter 12 andheater 13 (see Figure 5) which may be combined in one unit, the feedbeing to. the bottom of the cathode compartment where the electrolyte isadmitted to a relatively small bore perforated tube 14 extendingcentrally up the cathode compartment. The perforations in said tube areproportioned and spaced to ensure an even distribution of theelectrolyte up the cathode compartment. Around the perforated small boretube is disposed the relatively large bore diffuser tube j which rotateswith the heads h and 71 carrying either the cathodes or mandrels as inFigure 1, or the supplementary heads as in Figure 2. The diffuser tubeis also perforated to give an even diffusion of the incoming electrolyteinto the cathode compartment. By the means described, I obtain withinthe cathode compartment, an electrolyte of practically uniformtemperature and composition which is advantageous in obtainingsatisfactory metal deposits upon long mandrels. I

What I claim is 1. A vat for the electro-deposition of metalscomprising, in combination, an anode compartment, a cathode compartment,a filter diaphragm between the said compartments, a rotating head abovethe cathode compartment, mandrels constituting cathodes suspended fromsaid head and extending into the cathode compartment, means for rotatingsaid mandrels about their axes, a vertical perforated tube extending upthrough the cathode compartment, connected to the rotating head at itsupper end and providing a steady for the lower ends of the mandrels, andmeans delivering electrolyte within said perforated tube through whichit diffuses into the cathode compartment to overflow the filterdiaphragm into the anode compartment.

2. A vat for the electro-deposition of metals comprising, incombination, an anode compartment, a cathode compartment, a filterdiaphragm between said compartments, a main rotating head above saidcathode compartment, a plurality of separate heads carried by said mainhead, means for rotating said separate heads about their axes, aplurality of mandrels constituting cathodes suspended from said separateheads, means for rotating each mandrel about its own axis, heads for thelower ends of each group of mandrels, a vertical perforated tubeextending up through the cathode compartment and connected so that itrotates with the main head, with means upon the lower end of such tubefor supporting and steadying the heads beneath the lower ends of thegroups of mandrels, and means delivering eltiptrolyteup the interior ofsaid perforated tu e.

3. A vat for the electro-deposition of metals comprising, incombination, an annu lar anode compartment, a cathode compartment withinsaid anode compartment, a cylindrical filter diaphragm between the anodeand cathode compartments, a main rotating head with a gear drive theretoabove the vat, a plurality of separate heads carried by said main head,a common gear wheel centrally located for rotating all the separateheads about their axes, a plurality of mandrels constituting cathodessuspended in said cathode compartment from said separate heads, a

common gear wheel centrally located for rotating all the mandrels abouttheir own axes, heads for the lower ends of each group of mandrels, avertical perforated tube coaxial within the cathode compartment andconnected to the main rotating head with means upon such tube forsupporting and steadying the heads beneath the lower ends of the groupsof mandrels, and means delivering electrolyte up the interior of theperforated tube.

4. In a vat for the electro-deposition of metals as claimed in claim 2,a fixed perforatedtube extending up the interior of the verticalperforated tube to supply electrolyte to an annular space between thetwo tubes.

5. In a vat for the electro-deposition of metals as claimed in claim 2,hingedly mounted electric current conductor brushes contacting with theseparate heads to supply current thereto.

6. A vat for the electro-deposition of metals comprising, incombination, an anode compartment, a cathode compartment, a filterdiaphragm between said compartments, a rotating head above the cathodecompartment with individually rotated mandrels constituting cathodessuspended from said head, and screens also suspended from said headobstructing the direct path between the cathodes and anode material.

7. A vat for the electro-deposition of metals comprising, incombination, an anode compartment, a cathode compartment, a filterdiaphragm between said compartments, a rotating main head above thecathode compartment, separate heads individually rotated carried by saidmain head, mandrels constituting cathodes also individually rotated,suspended from said separate heads, and screens suspended from said mainhead obstructing the direct path between the groups of cathodes and theanode material.

In testimony whereof I have signed my name to this specification.

JACK HOLLINS.

